1. FIELD OF THE INVENTION
This invention relates to a new and improved integrated lunar materials manufacturing process and associated apparatus.
2. BRIEF DESCRIPTION OF THE PRIOR ART
The incentive for oxygen production on the moon is primarily the increased payload thereby made possible for other space missions which then do not have to carry all their propellant and life-support oxygen from earth. Also, oxygen produced on the moon requires much less launch energy and propellants to transport it to another space use, such as a space station, than oxygen launched from the deep gravity well of earth. An oxygen plant is, therefore, a key facility in a manned lunar base or colony.
Methods considered by applicants for lunar oxygen production use either: (1) reduction of iron-oxygen compounds with hydrogen or other reducing gases such as carbon monoxide or methane; (2) molten-phase electrolysis of the whole range of minerals found in surface-mined lunar regolith, or (3) direct thermal reduction of the regolith minerals. See Kesterke, D. G., U.S. Bureau of Mines Report of Investigations 7587, Reno, Nevada 1971.
The first method requires beneficiation and mineral separation steps upstream of the reduction reactor and chemical or physical techniques downstream to extract the oxygen and regenerate the reducing agents. The second and third methods do not require beneficiation but require much higher reduction process temperatures. Electrolysis requires handling and containing a corrosive, molten-salt bath and regeneration of earth-derived reagents or fluxes from the spent solids after electrolysis. See Weissbart, J. and Ruka, R., J. Electrochem. Soc. 109, No. 8, pp.723-726, August, 1962. Direct thermal reduction also poses high-temperature container corrosion problems, and, because of thermodynamic equilibrium limitations, requires that the oxygen be produced from the solids at low pressures. This invention addresses only the first method, namely hydrogen-reduction of naturally-occurring lunar iron-oxygen compounds.
A large base of prior-art technology is relevant to this method, namely those patents which teach various techniques for fluidized-bed reduction of iron ores and other steps in our process, such as electric heating and gas phase electrolysis.
Jukkola U S. Pat. No. 3,210,180 discloses a process of temperature control for fluidized beds used in reduction of iron ores.
Tomizawa U.S. Pat. No. 4,224,056 discloses a process of reduction of iron ores with carbon in fluidized beds.
Bessant U.S. Pat. No. 3,637,368 discloses a process of reduction of iron ores in fluidized beds by coating the ore particles with carbon and then gasifying the carbon at low pressures.
Whaley U.S. Pat. No. 3,295,956 discloses a process of refining iron ore particles by gas reduction in a fluidized bed reactor.
Mayer et al U.S. Pat. No. 3,346,365; Shipley U.S. Pat. No. 2,752,234; and Meissner U.S. Pat. No. 3,031,293 disclose processes of reduction of iron ores with carbon monoxide or hydrogen in fluidized beds.
Colombo et al U.S. Pat. No. 3,554,733 discloses a process of converting ferrous sulfate to sulfuric acid and iron oxide which is refined by reduction in a fluidized bed reactor.
Campbell U.S. Pat. No. 3,591,363 discloses a process of reduction of iron ores with hydrocarbons in radiant heated fluidized beds.
Colombo et al U.S. Pat. No. 3,649,245; Viviani et al U.S. Pat. No. 3,758,293; Wittman et al U.S. Pat. No. 3,167,419; and Schytil et al U.S. Pat. No. 2,893,839 disclose processes of refining pyrite ore by reduction in a fluidized bed reactor.
Gray U.S. Pat. No. 3,374,087 discloses a process of refining particulate iron ore containing a substantial amount of gangue by reduction in a succession of fluidized bed reactors.
Volk et al U.S. Pat. No. 3, 347,659 discloses a process of refining particulate iron ore by reduction in a fluidized bed reactor followed by grinding and screening.
Peras U.S. Pat. No. 3,148,572 discloses a process of refining hematite by reduction in a fluidized bed reactor to produce pure powdered iron.
Gorling U.S. Pat. No. 3,984,229 discloses a process of reduction of hematite or magnetite with gases in fluidized beds followed by agglomeration of the iron particles.
Old et al U.S. Pat. No. 2,894,831 discloses a process of refining iron ore by reduction in a fluidized bed reactor followed by melting in an electric furnace.
Hoffert U.S. Pat. No. 3,761,244 discloses a process of reduction of iron ore in successive stages in fluidized beds.
Knepper U.S. Pat. No. 3,896,560 discloses a two-stage fluidized bed reactor with nozzle tuyeres for reduction of iron ores.
Matsubara et al U.S. Pat. No. 3,928,021 discloses a process of reduction of iron ores in fluidized beds with utilization of thermal energy produced in the process.
Malgarini et al U.S. Pat. No. 4,082,545 discloses a process of reduction of iron ore particles with gases in fluidized beds followed by formation of iron sponge.
Hoffert U.S. Pat. No. 3,864,465 discloses a process of reduction of iron ore in fluidized beds with recovery and purification of hydrogen.
Prymak U.S. Pat. No. 4,509,103 discusses the dissipation of RF energy in ceramic capacitors but does not apply the heating technique to gases.
Kitagawa U.S. Pat. No. 4,439,929 discloses dielectric drying of a honeycomb ceramic but has no dielectric dissipation in the ceramic, only in the occluded moisture.
Blum et al U.S. Pat. No. 3,993,653 discloses a solid state electrolyte used in decomposing water and details of cell designs.
Williams et al U.S. Pat. No. 3,464,861 and Hegedus et al U.S. Pat. No. 4,396,480 disclose a solid state electrolyte used in a fuel cell.
Morrow U.S. Pat. No. 4,087,976 discloses a solid state electrolyte used in decomposing water.
Brothers al U.S. Pat. No. 4,659,435 discloses a solid state electrolyte used in decomposing water with integral heating.
Stucki U.S. Pat. No. 4,427,504 discloses a solid state electrolyte used in a process for production of nitric oxide.
This invention builds on this substantial prior art by adapting it to the special lunar requirements of (1) minimal consumption of earth-derived materials and ease of making up those unavoidably consumed; (2) extreme importance of thermal efficiency as the key to minimizing power generator launched weight; (3) complete absence of atmospheric air and water for cooling or for use in the beneficiation step and complete absence of any type of hydrocarbon fuels; (4) reduced gravity about 1/6 that of earth; (5) extreme emphasis on reliability with minimum manned attention.